Optical methods for distance and displacement measurements

Berkovic, Garry; Shafir, Ehud

doi:10.1364/aop.4.000441

Cited by 348 publications

(142 citation statements)

References 109 publications

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“…This method has been used around the year 600 BC by the Greek mathematician Thales of Miletus in measuring the height of the Giza pyramids and determining the distance to a ship that was in the sea (Berkovic & Shafir, 2012). This method is often used when measuring distances.…”

Section: Triangulationmentioning

confidence: 99%

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Distance Measurement Systems Using Lasers and Their Applications

Fonseca¹,

Baptista²,

Martins³

et al. 2017

APR

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Optical measuring systems came to offer new ways to determine distances, deformations or vibrations through more accurate and greater range methods. Technological progress has allowed a significant improvement of several components, including the optical ones. Thus, the development of essential measurement methods is crucial to keep up with technological advances.In this paper, the three basic methods of measurement are studied -triangulation, telemetry and interferometry, covering their main applications, advantages and disadvantages, and theoretically substantiating each of the methods. The results of simulation routines for each method are shown along this work. For the triangulation method we made two experiments which demonstrate the functioning of the method in measuring distances and surfaces.For the telemetry method, experimental setups were studied to apply the method of pulse telemetry and phase comparison telemetry to measure distances, Thus, it is intended to set up the basis for the future development of more complex methods.

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Section: Triangulationmentioning

confidence: 99%

“…1, the distance to the target can be determined from the similarity of the formed triangles. Note that these optical sensors, where the laser source and the detector are on the same device, are typically applied for measuring distances between 10 mm and 1 m (Berkovic & Shafir, 2012). …”

Section: Triangulationmentioning

confidence: 99%

Distance Measurement Systems Using Lasers and Their Applications

Fonseca¹,

Baptista²,

Martins³

et al. 2017

APR

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“…Several of them are implemented in commercial devices. Here we only mention a few reviews that cover many of the well known techniques at various levels of detail [55,56,57,58,59]. An interesting line of more recent development is based on Hänsch-type frequency combs, often with sub-mm accuracy, some of them developed for applications over very long distances in space (e.g.…”

Section: Laser-based Distance Measurementsmentioning

confidence: 99%

“…[58,78,79]), a technique which allows measuring a beat frequency resulting from single-frequency laser radiation, the frequency of which is linearly changed in time with a chirp rate γ c periodically repeated in a saw-tooth pattern.…”

Section: Comparison With Fmcw-ladarmentioning

confidence: 99%

Ranging with frequency-shifted feedback lasers: from $$\upmu$$ μ m-range accuracy to MHz-range measurement rate

Kim¹,

Ogurtsov²,

Bonnet³

et al. 2016

Appl. Phys. B

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We report results on ranging based on frequency shifted feedback (FSF) lasers with two different implementations: (1) An Ytterbium-fiber system for measurements in an industrial environment with accuracy of the order of 1 µm, achievable over a distance of the order of meters with potential to reach an accuracy of better than 100 nm; (2) A semiconductor laser system for a high rate of measurements with an accuracy of 2 mm @ 1 MHz or 75 µm @ 1 kHz and a limit of the accuracy of ≥ 10 µm. In both implementations, the distances information is derived from a frequency measurement.The method is therefore insensitive to detrimental influence of ambient light. For the Ytterbium-fiber system a key feature is the injection of a single frequency laser, phase modulated at variable frequency Ω, into the FSFlaser cavity. The frequency Ω max at which the detector signal is maximal yields the distance. The semiconductor FSF laser system operates without external injection seeding. In this case the key feature is frequency counting that allows convenient choice of either accuracy or speed of measurements simply by changing the duration of the interval during which the frequency is measured by counting.

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“…In this phase-measuring interferometry, the light wavelength (k) acts as the ruler and relates to the speed of light (c) as k = c/f with f being the optical frequency of light. Accordingly, the source frequency has to be stabilized to make the light wavelength stable during measurement, as realized for gaseous or solid-state lasers used with various stabilization schemes in industrial instruments [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Distance Measurements Using Mode-Locked Lasers: A Review

Jang

Kim

2018

Nanomanuf Metrol

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We present a progress review on the advance of distance measurements made at KAIST by making use of mode-locked lasers as the light source to meet ever-growing industrial demands on the measurement precision and functionality. Diverse principles exploited for the progress are described in this review with focus on four attributes: first, the optical spectrum of a mode-locked laser, distinctively called the frequency comb, permits multi-wavelength interferometry to be realized for absolute distance measurement up to several meters without losing the nanometer precision of well-established laser-based phase-measuring displacement measurement. Second, the frequency comb enables spectrally resolved interferometry for absolute distance measurement to be conducted with a nanometer resolution by Fourier transform analysis of the dispersive interference data captured using a spectrometer. Third, the mode-locked laser in the time domain appears as a train of ultrashort pulses, of which the time-of-flight is measured with a picosecond resolution by control of the pulse repetition rate with reference to the radio-frequency atomic clock. Fourth, the pulse-to-pulse cross-correlation occurring in the optical frequency domain is down-converted to the radio-frequency domain to achieve femtosecond pulse timing precision by means of dual-comb interference. All these principles based on unique spectral and temporal characteristics of ultrashort mode-locked lasers are anticipated to make contributions to the advance of nanotechnology particularly in manufacturing and metrology.

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Optical methods for distance and displacement measurements

Cited by 348 publications

References 109 publications

Distance Measurement Systems Using Lasers and Their Applications

Distance Measurement Systems Using Lasers and Their Applications

Ranging with frequency-shifted feedback lasers: from $$\upmu$$ μ m-range accuracy to MHz-range measurement rate

Distance Measurements Using Mode-Locked Lasers: A Review

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